George was born on 4 June, 1738. His mother was Augusta of Saxe-Gotha and his father was Frederick, Prince of Wales. As a child, George was taught to love music and was encouraged by his father to appreciate it. He was engaged by reasonably competent tutors, being taught Latin, French, German, history, mathematics, and religion. The tutors found him a difficult pupil, not exactly unwilling, but lethargic and incapable of concentration. At times he was silent and morose and when he was angry, he became obstinate and sullen. At twenty he still wrote like a child.
In March 1751, Prince Frederick caught a chill and died son afterwards. His widow became a rather possessive mother to the children, including George. Her friend and adviser was the vain and pompous John Stuart, Earl of Bute, who was regarded as "extremely handsome". According to Horace Walpole, "the beauty of his leg was constantly displayed in the eye of the poor captivated Princess". George implored Bute to help him and Bute never hesitated to mark his faults or to remind him or the immense responsibility of his calling. When George succeeded his grandfather in 1760, he took Bute's advice on every matter, ignoring other ministers with decades of political experience.
Unlike his two predecessors of the House of Hanover, George was raised in England and spoke English as his first language, which further endeared him to the people.
George fully understood the demands of his new position. In his accession speech, he declared:
"Born and educated in this country, I glory in the name of Briton."The speech had of course been written for him, but he personally inserted that particular line for he felt it described the life of dedication and duty he was prepared to live.
As soon as George III ascended the throne, the search for a suitable wife intensified. Colonel Graeme was sent to the various Royal courts of Europe with a mission of finding a bride for the King. During his stay in Mecklenburg, he reports the charms possessed by a seventeen-year-old Princess Charlotte. The King was convinced and announced to his Council in July 1761 his intention to wed the Princess; Lord Hardwicke was sent to Mecklenburg to solicit her hand in the King's name. Charlotte's brother, Adolf Frederick IV, Duke of Mecklenburg-Strelitz, received the King's representatives with every honour that the little court was capable of showing for the prospect of such prominent alliance was very pleasing.
Like his predecessors, George was a sensual man. He appreciated feminine beauty, but his high sense of morality would not allow him to indulge in his fancies. In 1759, George fell in love with Sarah Lennox, a daughter of the Duke of Richmond. He longed to marry her, but Bute said "no" and dutiful George obeyed, although his infatuation continued for some years. He told Bute:
"It is entirely owing to a daily increasing admiration of the fair sex which I am attempting with all the philosophy and resolution I am capable of to keep under..."Persistent rumours maintain that on 17 April, 1759, George has secretly married a quakeress called Hannah Lightfoot, who is said to have borne him three children. However, if this were true, his subsequent official marriage would have been bigamous and it is unthinkable that a decent and dutiful monarch with high morals like George would have contracted a bigamous marriage. In 1761, George settled hastily on Charlotte of Mecklenburg-Strelitz. George fulfilled his marital duties in the same conscientious way as he fulfilled his kingship. They had 15 children. The first, who is to succeed him as King, was born eleven months after the wedding.
Marriage and fatherhood helped George to overcome his sense of insecurity. He was interested in music and the technique of agriculture. He created model farms at Windsor, which earned him the nickname of "Farmer George". He collected drawings, coins, medals, watches, and model ships. Queen Charlotte was interested in music too, and could perform on the clavichord. She was well-read in history and had some knowledge of botany, but she was particularly skillful with her needle. In concern to shield his wife from outside influences and intrigues and his determination that she should be wholly devoted to him alone, George kept Charlotte as much as possible from making acquaintances in her new fatherland. George enjoyed a quite evening at home and by 10 o'clock the Royal couple would go to sleep.
In 1762, George was ill from January until July, suffering from fever, coughing, a rapid pulse, insomnia, and loss of weight. In January 1765, George suffered from "a violent cold", insomnia, and stitches in his breast. At times George felt better, was cheerful and good-humoured; but he was recurrently stricken by new relapses. Early 1766 he had another relapse, but soon afterwards made a full recovery. Apart from these illnesses, George enjoyed excellent health and kept his figure trim by a Spartan diet and plenty of exercise.